This application is a feasibility study for high impact research project to develop behavioral assays for studying hearing and more complex behaviors in the Zebrafish (Danio rerio). This is a feasibility study because an approach to study behavioral responses in zebrafish has never been attempted and, while preliminary evidence that these fish can be trained for relatively complex tasks is tantalizing, there is no guarantee of success. It is high impact because the zebrafish is an increasingly useful and important vertebrate model system for studies of vertebrate genetics. Most significantly, as new genes are discovered that has potential impact on behavior of growing and adult animals, it will be necessary to have ways to test and analyze the impact of the genes on sensory, motor, and central nervous system processes. However there are no highly quantifiable and reliable methods to assess the overall sensory and motor responses of these animals. The purpose of this application is to develop rigorous behavioral procedures for unrestrained, freely moving animals to permit access to such higher order processes as memory, attention, and learning. These kinds of processes can only be measured using psychophysical testing of the kind we propose to develop here. Over the course of this study we will develop an approach that leads to auto-shaping of animals so that they respond to a selected stimulus (a sound) by approaching a food source. The nature of the behavioral response will indicate whether the fish has or has not detected the signal, and we can thus assess many aspects of hearing and the auditory system. Once developed, the procedure will be applied to testing fishes with various mutations of the ear and auditory system to assess their effects on hearing in growing and adult animals. Moreover, once developed the basic procedure will have broad usefulness for assessment of other sensory, motor, and higher order functions.